Altman et al. (U.S. Pat. No. 3,792,373) teaches a metal vapor laser in which the room temperature Brewster windows are isolated from the vapor to prevent metal condensation on the windows. The Brewster window is attached to the end of the electrode support tube. At the other end of the electrode support tube is a cathode electrode with a spherical surface. The laser tube is sealed to the electrode support tube by a connecting sleeve assembly with the help of O-rings, pressure limiting rings and threaded collars. The electrode support tube may be removed by disengaging the tube from the correcting sleeve assembly.
Hall et al. (U.S. Pat. No. 4,185,254) teach interchangeable and adjustable windows. They use O-rings which make a vacuum-tight seal between a stainless steel body and each window. Huchital et al. (U.S. Pat. No. 3,745,483) teaches replaceable metal end members having electrodes and Brewster windows. The Brewster windows are sealed to the end members and are not removable. The end members are secured to a glass cylinder through heat resistant gaskets. Hermetic seals are provided by interlocking flanges, overlapping collars, and bolts on the glass and metal members. Levine (U.S. Pat. No. 4,093,927) has Brewster angle windows on end plates which sandwich the rest of the laser assembly and which are drawn together by tie rods, thus placing gaskets under compression forming a vacuum chamber. The problem with these lasers is that when a part of the end assembly needs to be replaced, the laser will need to be evacuated and refilled with gas. This reprocessing is impossible with the prior art. For example, the Brewster window assembly may need replacing, because of breakage or color center formation. Often defects in a Brewster window are not discovered until the laser is filled and operated.
It is an object of the present invention to create a modular end assembly for gas lasers in which the Brewster window, and gas feed tube are each replaceable without destroying the supporting flange and the other elements, so that the laser may be reprocessed.
It is a further object of the invention to create this modular assembly so the replacement of parts is simple and does not require welding of parts to the supporting flange.